Physiological responses of spinach leaves to low oxygen conditions: a clearer picture

We are investigating the physiological effects of oxygen deficiency imposed at root level, in plant leaves. Aim of this study is to explore if fermentative metabolism in response to oxygen deficiency stress can be induced also in leaves, and if so, the possible relationships among anaerobic genes (Adh1, Ldh1) transcription and translation. Spinach (Spinacia oleracea) plants are grown in hydroponic culture using the floating system. Hypoxia is spontaneously induced, simply ceasing to oxygenate the nutritive solution; anoxia by bubbling gaseous nitrogen into it. Under normoxia, the level of O2 in the nutrient solution of the hydroponic system is about 7 mg/l. Upon uspending aeration there is a gradual fall in O2 level in the solution, and hypoxia (1-3 mg/l) is reached after approximately 12h. When oxygen deficiency stress is induced by aeration with N2 gas, the level of O2 fall to 2 mg/l within 2h and the complete anoxic condition (O2 < 1 mg/l) is reached after approximately 4h.